Fuel pump

Patent metadata

Field	Value
Publication number	US-2016265495-A1
Application number	US-201415033334-A
Country	US
Kind code	A1
Filing date	Oct 16, 2014
Priority date	Oct 31, 2013
Publication date	Sep 15, 2016
Grant date	—

Abstract

A projection of a suction end cover has an outer circumferential surface serving as a sealing surface to be connected with a suction filter. A suction flow path is configured by an introduction hole in a bottomed cylindrical shape, and a connection hole. The introduction hole extends from the distal end of the projection of the suction end cover toward a pump chamber. The connection hole connects the introduction hole and the pump chamber. The introduction hole has a bottom surface that is located axially between a slide inner surface of the suction end cover and a bottom surface of a recess. The suction flow path can be increased in sectional area enough to reach a position in immediate front of the pump chamber with no change in outer diameter of a housing. By reducing fuel flow speed in the suction flow path and suppressing negative pressure in the suction flow path, generation of fuel vapor in the suction flow path can be inhibited even in a large flow rate area.

First claim

1 . A fuel pump configured to suction, pressurize, and discharge fuel, the fuel pump comprising:
a cylindrical housing a suction end cover provided at a first end of the housing, and having a cylindrical projection extending outward from the housing and a suction flow path penetrating the projection and communicable with an exterior; a discharge end cover provided at a second end of the housing and having a discharge flow path communicable with the exterior; a brushless motor provided between the suction end cover and the discharge end cover in the housing; a casing defining a pump chamber that partitions between the suction end cover and the casing in the housing and communicates with the suction flow path, and having a discharge hole penetrating from the pump chamber to the discharge end cover; and an impeller rotatably provided in the pump chamber and including a disc-shaped boss torque-transmittably coupled to an end of an output shaft of the brushless motor, the output shaft inserted through the casing and extending into the pump chamber, a plurality of vanes projecting radially outward from the boss in different directions, and an annular ring surrounding the vanes, wherein the suction end cover has a recess depressed opposite to the impeller from a slide inner surface slidable with respect to the impeller, the recess of the suction end cover has a bottom provided with a thrust bearing receiving the end of the output shaft, the projection of the suction end cover has an outer circumferential surface serving as a sealing surface to be connected with a suction filter, the suction flow path has an introduction hole having a bottomed cylindrical shape and extending from a distal end surface of the projection of the suction end cover toward the pump chamber, and a connection hole penetrating from the introduction hole to the pump chamber, and assuming that the impeller has a rotational axis in an axial direction, the introduction hole has a bottom surface located between the slide inner surface of the suction end cover and a bottom surface of the recess in the axial direction.

2 . The fuel pump according to claim 1 , wherein the introduction hole has an inner diameter of not less than 9 mm.

3 . The fuel pump according to claim 1 , wherein the vanes divide a space between the boss and the ring of the impeller into a suction vane groove adjacent to the suction flow path and a discharge vane groove adjacent to the discharge hole, and
a ratio of a radial width of the suction vane groove to an outer diameter of the impeller and a ratio of a radial width of the discharge vane groove to the outer diameter of the impeller are not less than 10%.

4 . The fuel pump according to claim 1 , wherein the projection of the suction end cover has an outer diameter of not more than 12 mm.

5 . The fuel pump according to claim 1 , wherein the suction end cover has a wall adjacent to the pump chamber, and the wall has a pressurization flow path configured by a C-shaped groove extending circumferentially when viewed in the axial direction, and
a value obtained by dividing a depth of the pressurization flow path by a radial width of the pressurization flow path is from 0.28 to 0.40.

6 . The fuel pump according to claim 1 , wherein the recess of the suction end cover has an inner diameter of not more than 8.5 mm.

7 . The fuel pump according to claim 1 , wherein the number of the vanes is not less than 41.

8 . The fuel pump according to claim 1 , wherein the projection of the suction end cover has an axial length of not less than 3.5 mm from an outer peripheral edge of the suction end cover.

9 . The fuel pump according to claim 1 , wherein the suction end cover is formed by applying alumite treatment to an outer surface of an aluminum alloy molded product.

Assignees

• Denso Corp

Inventors

• Nagata Kiyoshi
• Oota Yuuichirou
• Sakai Hiromi

Classifications

• F02M37/22

  Arrangements for purifying liquid fuel specially adapted for, or arranged on, internal-combustion engines, e.g. arrangements in the feeding system · CPC title

• F02M37/20 Primary

  characterised by means for preventing vapour lock · CPC title

• F04D3/005

  with a conventional single stage rotor · CPC title

• F04D29/708

  specially for liquid pumps · CPC title

• F04D29/043

  Shafts · CPC title